1. Field of the Invention
The present invention generally relates to damping arrangements, such as dampers used in shock absorbers or steering assemblies, used in motor vehicle applications. More particularly, the present invention relates to a valve assembly used with such dampers that operates to remove undesired oscillations during use caused by an admixture of air and damper medium.
2. Description of the Related Art
The technology that has been used to date within the field is described in, for example, S9800775-0, S0400012-1, EP504624-A2 and EP400395-B1. The valves in question are described in these documents as pilot-controlled, with damping of the pilot cone not being described in certain cases, but with a solenoid's armature being damped in its cylinder. In other cases, as in EP400395, the damping is described as a throttling between two chambers. Among other things, it is common to the known technical solutions that the damping arrangement is located on the low pressure side, which is downstream of the valve function that is to be damped.
The problem with the valves in these references is that their damping is based on the sum of hydraulic damping in the solenoid or in its vicinity, and friction. The shock absorbers or steering dampers, etc, that are used within the car industry do not usually have so-called gas-separating pistons, for which reason the hydraulic fluid becomes saturated with gas. After hard driving with such dampers, gas collects in pockets and closed spaces and the volume of gas increases the lower the pressure. This means that the damping that relates to valve functions on the low pressure side can be lost under the circumstances. Remaining friction is insufficient to damp the valve function, which can cause oscillations with frequencies within the range 400-1500 Hz. This sound is particularly irritating to the human ear and is not acceptable to car users and car manufacturers. Increased friction has been tested and has been found not to solve the problem in a correct way. Certain features, aspects and advantages of some embodiments of the present invention are intended to solve this problem, among others.
There is also a desire for the valve in question, for example a proportional valve, to be able to be incorporated in a main valve in an integrated and space-saving way.
Certain features, aspects and advantages of some embodiments of the present invention also solve this problem.